Corrosion is a byproduct of an undesirable chemical reaction when a material such as a metal having machined and/or painted surfaces is exposed to the environment. Exposure of the metal to water or water vapor can cause oxidation of the metal or rust. Corrosion can cause the structure integrity of the material to fail during use leading to unsafe conditions and can cause unsightly rust spots on the surface of the material. Further, corrosion also leads to equipment down time in order to rectify the structural integrity issues.
Volatile corrosion inhibitors (VCIs) have been used to prevent corrosion since World War II but have not worked well. VCI chemicals can be in powder, liquid, foam or sprays and are often surrounded by a film or bag. If VCIs are thinly applied, they can be easily washed away or if they are thickly applied then they are generally messy and difficult to remove.
An adhesive with additive delivery system is described in U.S. Pat. No. 5,705,566 (the '566 patent) issued on Jan. 6, 1998. The '566 patent discloses an adhesive mixture includes a block copolymer hot melt adhesive and particles of a vapor corrosion inhibitor mixed therein to protect products against corrosion. The adhesive is used to seal flaps of containers together, secure carpet to the floor of a vehicle, secure nonwoven fabric to a shrink film so that the additive is released when the shrink film is shrunk around a product to be protected, or used as an adhesive on a tape, so that the product is protected when the tape is wrapped around the product. However, the additive delivery system can fail should the film rip during use.
Accordingly, there is a need for a system that efficiently provides a water-base film that includes a VCI that will adhere to the metal even if the film is ripped or punctured.